Electrocardiographic electrode



Dec. 16, 1952 c, LEEC'H 2,621,657

ELECTROCARDIOGRAPHIC ELECTRODE Filed Sept. 19, 1950 53M W F 2 Patented Dec. 16, 1952 UNITED STATES PATENT- OFFICE ELECTROCARDIOGRAPHIC I ELECTRODE Clifton B. Leech, Barrington, R. I.

Application September 19,1950, Serial No. 185,579

4 Claims. (01. 128-417) This invention relates to an improved electrode for use in obtaining electrocardiograms.

One object of the invention is to provide an electrode with self-contained means for applying paste to the skin of a patient within a'controlled area to eiiectually secure conduction therefrom.

Another objectis to provide an electrode of the type indicated for applying a thick layer of the paste to the skin of a patient and causing the skin to be lightly gripped without likelihood of the electrode slipping, so as to prevent interruption of conduction and avoid the production of artefacts.

Another object is to provide a device of the type indicated in which the area of contact of the electrode paste is controlled and restricted to prevent so-called bridging between adjacent areas whereby to obtain the desired local potential.

Another object is to provide an electrode that avoids the necessity for smearing various portrode for obtaining records of the potential of local areas of the cardiac muscle without interference by the potential of adjacent cardiac muscle.

Another object is to provide a device of the type indicated which may be adapted for obtaining leads from the patients extremities by releasably attaching the electrode thereto.

In obtaining electrocardiograms it has been the usual practice to smear a layer of paste on the patients skin for contact with the surface of the electrode, whereby to effect conduction through the lead wire to the electrocardiograph. In most instances it is diflicult to confine the spread of the paste to a limited area without overlapping and thereby causing interference by the potential of adjacent cardiac muscle. In such instances bridging occurs so that the potential of adjacent areas is recorded and prevents ob taining the desired local potential. Moreover,. due to the necessarily thin layer of paste, small 2 movements between the skin and electrode are liable to interrupt conduction and consequently produce artefacts which distort the electrocardiogr'am. H

To avoid the above-noted difiiculties and-deficiencies in the usual method of obtaining electrocardiograms, the present invention contemplates the use of a precordial electrode provided with a chamber for containing a substantial amount of paste with means for connecting it to the leads of an electrocardiograph. The pastechamber is preferably mounted on an insulated handle for conveniently applying the electrode In the preferred construction, the cone to use. tainer for the paste is covered with a screen of conducting material, such as copper wire mesh;

through the interstices of which the paste may exude to be applied directly to the skin of the patient and thus secure efficient conduction. The wire screen-cloth or other perforated covering also has the further advantageous effect of preventing slipping of the contact portion of the electrode on the skin of the patient so as to confine its application to a restricted area, as well as to prevent artefacts.

Further objects and advantages of the-invention are set forth in the following specification which describes a preferred form of construction of the present improved electrode in a form to adapt it to be held manually for precordial use or to be releasably attached to the extremities.

The twoforms of the invention are illustrated by the accompanying drawing in which:

Fig. l is an enlarged elevational view showing the electrode provided with a handle;

Fig. 2 is a similar view of the upper portion of the electrode shown partly in section to illustrate the structure and arrangement of its parts;

Fig. 3 is a plan view of the container for'the paste showing the binding post for connection'of the electrical conductor or lead wire thereto; and

Fig. 4 is an elevational view in reduced scale showing a modified form of paste-container provided with a resilient clip for attaching it to the patients extremities.

Referring to the drawing, the present electrode may be constituted by a cylindrical handle 2 constructed of wood or other dielectric material such as plastic or the like. end of, the handle 2 is a stud 3 formed with a cylindrical seat or disk 4 having a knurled periphery and a screw-threaded projection or neck 5 thereabove for securing the paste-container, designated generally by the reference character 6, to the handle 2. The head of the instrument comprising the paste-container 6 is constructed Screwed into the upper" in two sections 8 and 9, the lower saucer-shaped section 8 having an axial screw-threaded bore It to adapt it to be screwed onto the projection or neck 5 at the end of the handle 2. Preferably, the bore in the base portion 8 is of a diameter and thread formation proportioned to adapt it to screw onto the neck of a collapsible tube of conventional type used as a reservoir for containing the electrode paste; it being noted that Figs. 1, 2 and 3 of the present drawing illustrate the electrode in substantially double size. The outer circumference of the base-portion 8 of the paste-container 6 is also screw-threaded at If to adapt it to receive the upper cover-section'or cap 9 as indicated in Fig. 2. The upper coversection or cap 9 consists of a cylindrical ring I'Z formed with screw-threads on its interior and mounting a crowned top [3 constructed of wire screening of fine mesh. The wire mesh may be soldered or otherwise permanently fastened within the interior of the cap-ring 9. The wire screening of the'crowned top 13 may be of conducting materiaLsuch as copper wire mesh, and-may be plated with chromium or other material to prevent corrosion.

A stud l5 has areduced end driveninto a bore at one side of the base-section 8 0f the pastecontainer '6, or otherwise suitably fastened-thereto, with its larger portion having an'openinglfi through which the terminal H of a lead wire 13 may be inserted, a thumb-screw I 9 being adapted to be screwed th-ereagainst to provide a binding post 'for connecting the electrode with the electrocardiograph, seeFig. 3.

Fig. 4 illustrates a modified-form of construction of the present improved electrode to provide a clip for attaching it toa limb o'f the patient. In this construction of the device the chamber or container 6 for the paste is of substantially the same form and arrangement as that shown in Fig. 2, being composed of a base section 21 and a cap section 22 with a perforated or screencloth closure 23 at the'top of the latter. In the construction shown in Fig. ithe base portion 2| of the paste-container is formed with aninterior threaded bore similar to that of the electrode shown in Fig. 2 for receiving the threaded shank 24 of a stud 25, shown by dotted'lines in Fig. 4. The stud 25 has a knurled head 25 for screwing its shank into the base section 2| to clamp the clip 20 against the bottom of the-container. The clip 20 may be constructed of relatively thin spring-metal with a circular central portion having an opening for receiving the threaded shank of the stud 25. The paste-container is provided with "a binding post 2'! similar to that described in connection with the electrode shown in Figs. 1, 2 and 3.

The method of using the electrode for taking electrocardiograms is as next explained. The paste-container '6 is first filled with a supply of non-greasy paste such .as jellied sodium chloride which may be entered through thebore in the bottom of the section '8 of the container. For this purpose a collapsible tube containing the pastemay have its neck screwed into the threaded bore l0 and the material squeezed therethrough, it being understood that the cover or cap 9 .is screwed only part way down on the base 8.during filling of the container so that a large charge may be supplied thereto. The container 6 is then screwed back onto the neck 5 at the end of the handle .2. The lead wire to the electrocardiograph is then connected to the binding post I5 and the electrode is ready for use.

The container shown in Fig. 4 may be filled in the same way by removing the stud 25 from the bore in the bottom of the section 2|, whereafter the stud is screwed into place to clamp the clip 20 to the container. The arms of the clip 20 are sprung around the patients limb, for example at the wrist or ankle, and the lead connected to the binding post 21.

In taking the electrocardiogram the precordial electrode is held by the hand 2 and the screencloth l3 at the end of its head placed against the skin of the patient. The screen-cloth I3 may have slight flexibility so that when pressure is applied the paste in-the container 6 will exude through the interstices in the wire mesh to contact the skin and provide good conductivity through the paste to the wire lead.

In the same way the container shown in Fig. 4 may beplaced on the patients limb by springing the arms of the clip 20 therearound to provide sufficient pressure for insuring firm contact between the paste and the skin. If required, the cap on the container may be screwed down slightly onto its base-section 8 for insuring proper contact of the paste with the skin. The

screw-threaded connection between the cap 9 and'the base 8 0f the container also provides that when the supply'of the paste'in the containeris depleted the cap may be screwed down to force the paste through the screen-cloth. The paste-container 6 is designed to hold a large supply of the paste so that the electrode may be used repeatedly for taking numerous electrocardiograms until the supply is exhausted when itmay be conveniently replenished. The handle 2 for manual use of the precordial electrode being of wood or otherdielectric material, insulates the electrode to prevent electrical currents reaching it from the hand of the operator, while providing convenient means for manipulating the device.

It will be observed from the foregoing description that the present invention provides a particularly efficient device of the type indicated whichis most convenient to use either as a precordial electrode or for making contact with the skin of a patients extremities. The improved electrode is simple in construction, economical to manufacture andmost convenient to use. By its use, initial preparation of the patient is not required, resulting in the saving of time and effort on the part of the technician and also conserving the time of the physician himself. Its use also has the advantage of preventing artefacts due to interruption of conduction and also preventing bridging or interference such as would be caused by overlapping of the paste. Stated briefly, accurate records of the potential of the cardiac muscle may be obtained without interference from the potential of areas adjacent thereto.

The container for the paste is convenient for filling and provides a relatively large supply of paste, thus permitting numerous electrocardiograms to be obtained within a minimum of time, and saving the time of both the technician and the patient.

While the improved device isherein shown and described as embodied in a preferred form of construction in two dii ferent forms, it is to be understood that modifications may be made in the structure and arrangement of the parts of the device without departing from the scope of the invention as expressed in the following claims.

Therefore, without limiting myself in this respect, I claim:

1. An electrode for use in electrocardiography consisting in a container for paste comprising a hollow cylindrical lower section of substantially saucer-shape with its outer wall provided with screw-threads, an upper section in the form of a ring having an imperforate outer wall provided with screw-threads engageable with the screwthreads on the lower section, a binding-post mounted on one section for connection thereto of an electrical conductor, and a domed wall of screen-cloth surmounting said ring to provide a multiplicity of interstices through which the paste may be extruded by pressing said screencloth against the skin of a patient, said upper ring-section being adapted to screw down onto the lower section to confine the paste therein and reduce the space within the container as the paste becomes depleted so as to invariably maintain said paste completely filling the upper section in contact with the screen-cloth dome thereon.

2. An electrode for use in electrocardiography consisting in a container for paste comprising a cylindrical lower section with a shallow recess in its interior and screw-threads on its outer wall, a separate cap-section having an imperforate cylindrical wall formed with screw-threads on its interior engageable with the screw-threads on the lower section to adapt it to be screwed down thereon, a dome-shaped flexible wall of metal screen-cloth surmounting the top of the cap-section and secured thereto at its lower edges, and a binding post on the lower section for attachment of an electrical conductor thereto, said cap-section adapted to be screwed down on the lower section to confine the paste therein and reduce the capacity of the container when the paste therein becomes depleted so as to force the paste up into the dome and maintain it in contact with the screen-cloth surmounting the a :formed by an annular metal wall having a convex covering of screen-cloth joined thereto and 'surmounting its top, said annulus provided with screw-threads on its interior to adapt it to be screwed down on the lower section to confine the paste therein and reduce its capacity as the paste becomes depleted to maintain the paste in contact with the screen-cloth after repeated use of the device, said bottom section having a screw-threaded opening in its bottom for filling the container with paste, a handle having a screw-threaded neck adapted to be screwed into said last-named opening to close the container and provide for convenient manipulation of the device, and a binding-post fast on said lower section for attaching an electrical conductor to said lower section of the container.

4. An electrode of the type indicated consisting in a metal base-section having a cylindrical wall with screw-threads formed thereon, an upper section comprising a metal ring formed with screw-threads engageable with the threads on the lower section, said upper section having a dome-shaped covering of screen-cloth fastened to its upper wall, a binding post on the base section of the container for connection of an electrical conductor, and an extended handle having a threaded neck at its end screwed into a central threaded opening in the base-section of the container and formed with a flange abutting the bottom thereof, said handle being removable for filling the container through the threaded opening in the bottom of said base-section, and said upper section being adapted to screw down onto the base section when the paste in the container is depleted in use whereby to confine the paste and force it against the upper screen-cloth dome of the container to maintain it in contact therewith.

CLIFTON B. LEECH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,076,210 Kerr et a1. Got. 21, 1913 1,117,207 Mars Nov. 17, 1914 1,480,353 Wappler Jan. 8, 1924 1,889,271 Zerne Nov. 29, 1932 2,126,070 Wappler Aug. 9, 1938 2,555,037 Jensen May 29, 1951 

